Control valve mechanism for pressure operated actuating device



July 14, 1959 M. J. DUER H 2,894,501

CONTROL VALVE MECHANISM FOR PRESSURE OPERATED ACTUATING E ICE Filed Nov. 29, 1956 I 2 Shets-Sheet 1 aux HAND PUMP.

mmvroa g 'fiozzzir J @2162 g k 5 BY Q E M u a u ATTORNEY July 14, 1959 M. J. DUER 2,894,501

CONTROL VALVE 'MECHANISM FOR PRESSURE OPERATED ACTUATING DEVICE Fil ed Nov. 29, 1956 2 Sheefs-Sheejt 2 OVEARUN/V/N j CLUTCH HAND PUMP a ii BY $702224 cfflzzez' U 5% m $1 a h ATTORNEY United States Patent CONTROL VALVE MECHANISM FOR, PRESSURE OPERATED ACTUATING nrwrcn Morris J. Duer, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 29, 1956, Serial No. 625,063 19 Claims. (Cl. 123-179) This invention relates generally to a fluid pressure system and more particularly to a control valve mechanism adapted to control the supply of pressurized fluid to a pressure operated actuating device adapted to drive a load device.

In fluid pressure systems where the load device is disconnectable from and adapted to subject the actuating device or motor to extreme load conditions, it is desirable to provide a control valve mechanism adapted to either limit or prevent the flow or pressurized fluid to the motor when the motor is operating under substantially unloaded conditions. Otherwise, the unloaded motor is subjected to detrimental and destructive overspeed operating conditions, and in applications where the supply of pressurized fluid is limited, such unloaded operation also results in the rapid consumption of the limited pressure supply. In its broader aspects the invention contemplates an improved control valve mechanism for such a pressure system including a valve member automatically operable in response to pressure demand or load requirements of the pressure operated device between two fluid supply positions.

The invention has particular application toa hydraulic engine starter system similar to that shown and described in United States. patent application, S.N. 549,635, filed November 29, 1955, in the names of Clyde A. Ditmer and Morris J. Duer and entitled Fluid Pressure System and Pump, and the invention is herein shown and described in such an operational environment for the purposes of illustration. However, its use is not limited to such engine starter systems, the invention being considered adaptable to fluid pressure actuator systems generally.

Engine starting systems of the above-mentioned type include a starting device which is mounted on and adapted to selectively drive an internal combustion engine during its starting phase of operation. The starting device is preferably of the type shown and described in United States patent applications, S.N. 545,186, filed November 7, 1955, in the names of Morris J. Duer and Clyde W. Truxell, and SN. 545,348, filed November 7, 1955, now Patent No. 2,847,984, in the name of Raymond A. Gallant, both entitled Hydraulic Engine Starting Device. Such a hydraulic device includes a hydraulic motor, a means including a shiftable overrunning clutch type pinion drive adapted to drivingly connect the motor to drive the associated engine during starting and automatically operable to disconnect the motor from the engine upon the starting of the engine, and a valve mechanism selectively operable to control the flow of pressurized fluid to the motor from a suitable but limited source of fluid pressure including a pressure accumulator.

With respect to such hydraulic engine starter systems,

the invention contemplates an improved control valve mechanism operable by either local or remote control means to first shift the starter pinion towards engagement with the engine driven gear, to then supply a limited quantity of pressurized fluid to the fluid motor to insure driving engagement between the starter pinion and the engine 2 driven gear, to subsequently deliver pressurized fluid to the motor in suflicient quantities to achieve engine starter speeds, and operable to close automatically in response to the reduced pressurized fluid demand of the starter motor upon starting of the engine.

The foregoing and other objects, features and advantages of the invention will become apparent from the following detailed description of several preferred embodiments thereof in which reference is made to the attached drawings, in which:

Figure 1 is a somewhat diagrammatic view showing a hydraulic engine starter system embodying the invention with portions of several of the elements broken away and in detailed section; and

Figure 2 is a view similar to Figure 1 showing a modified form of the invention.

Referring more particularly to the drawings, the hydraulic engine starter system shown in Figure 1 includes a hydraulic engine starter device 20 of the type shown and described in the aforementioned patents. The hydraulic starter device 29 comprises a fluid motor 21 having a rotary cylinder barrel 22 having a plurality of axially extending bores therein, not shown, which recip rocably mount a plurality of pistons 23 which thrustably engage an inclined thrust plate 24. A valve plate 25 having a fluid inlet port 26 and a discharge port 27 is adapted to sequentially supply and exhaust pressurized fluid to and from expansible chambers formed in the individual cylinder bores intermediate the valve plate and the pistons thereby reciprocating the pistons which coact with the thrust plate to effect rotation of the cylinder barrel. This rotation of the cylinder barrel drives a shaft 28 which slidably but nonrotatably mounts an overrunnin-g clutch drive mechanism 29 which is adapted to drive a starter pinion gear 30 mounted thereon. An actuating lever assembly 31 associated with starter unit is adapted to shift the drive mechanism 29 axially on the shaft 28 to carry the pinion gear 30 into driving enga ement with an engine-driven ring gear, not shown.

A control valve 32 is associated with the motor 21 and is operable to control the supply of pressurized fluid to the inlet port 26 of the starter motor when the pinion gear 33 is in driving engagement with the engine ring gear. The pressurized fluid thus supplied causes the motor to drive the engine with suflicient rotational speed to effect the starting of the engine and is returned from the outlet 27 by piping 33 to one inlet 34 of a hydraulic fluid reservoir 35. An outlet 36 provided for the reservoir 35 is connected through suitable piping 3'7 and 38 to the inlets of a hand-operated pump 39 and a power driven pump 40, respectively. The pump 40 is adapted to be driven by the engine or by some auxiliary power source such as an electric motor. The two pumps 39 and 40 are connected in parallel, their outlets being interconnected through suitable piping 41 and 42, respectively, and are in turn connected through piping 43 and a manually operable valve 44 to a pressure accumulator 45 and through piping 46 and fitting 47 to the inlet port '78 of the control valve mechanism 32. Suitable check valves, not shown, are preferably associated with the pumps 39 and 4t and prevent reverse flow through these pump units. A suitable pressure unloading valve, also not shown, is associated with the engine driven pump 40 and is operable when the accumulator pressure reaches a predetermined level to unload this pump by returning the pumped fluid through piping 48 to a second inlet 49 provided in the reservoir.

In accordance with the invention, the control valve mechanism 32 comprises a valve body or casing 50 having two valve bores 52 and 54 extending therethrough in side by side spaced parallel relation. The bore 52 is sealed at one end by a cap plate 56 suitably secured and sealed with respect to the valve body. The opposite end of the bore 52 is sealed by a pipe plug 58. A snap ring 60 is mounted in an inwardly opening groove formed intermediate the ends of the bore 52 and serves as'an abutment or stop for a spool-type valve member 62 which is reciprocably mounted in the bore 52 intermediate the cap plate 56 and the ring 60. The valve member 62 is provided with a fluid flow controlling reduced diameter portion land 63 intermediate its ends and a second reduced diameter portion 64 adjacent its cap plate end. This second reduced diameter serves as an internal spring guide for a spring 66 which is compressibly interposed between the cap plate and the shoulder on the valve member formed by its reduced diameter end portion 64 and biases the valve member towards the stop ring 60. It will be noted that the closed ends of the bore 52 coact with the valve member 62 to form two oppositely opposed expansible chambers 68 and 70. As explained in greater detail below, the valve member 62 is reciprocable in accordance with pressure diflerential occurring between the chambers 68 and 70 to control the flow of pressurized fluid to the starter motor. In its valve-closed position the reduced diameter end portion 64 of the valve member 62 abuts the cap plate 56 and the opposite large diameter end thereof is effective to prevent fluid flow between an intermediate valve port 72 and a valve outlet port 74 opening on the valve bore 52. In its full-opened position the valve member abuts the snap ring 60 and the reduced diameter land portion 63 permits fluid flow between the valve ports 72 and 74. The valve outlet port 74 is connected, as shown, to the inlet port 26 of the starter motor by piping 76.

The valve bore 54 is closed at its end adjacent the chamber 68 by a pressure fitting 77 and is undercut intermediate its ends to provide a valve inlet chamber 78 which, as indicated above, is connected to the pressure supply system by the fitting 47 and the piping 46. The inlet chamber or port 78 is also connected to the expansible chamber 68 by an interconnecting passage 79 pro vided in the valve casing. A second undercutting of the valve bore 54 longitudinally spaced of the inlet cham ber 78 forms an intermediate valve chamber or port 80 which is connected to the valve port 72 by an interconnecting passage 81 provided in the valve casing. The valve chamber 80 is also connected to the expansible chamber 70 by a relatively small passage 82 extending therebetween in the valve body.

A valve member 83 is reciprocably mounted in the valve bore 54 and is sealed with respect thereto by suitable means such as the O-rings 84 which are mounted in spaced annular grooves opening on the valve bore 54. The end of the valve member 83 opposite the fitting 77 projects from the valve body and has a lost-motion pin-and-slot connection indicated at 85 with the starter drive shifting lever assembly 31. A bore 86 extends axially of the valve member 83 from its end adjacent the fitting 77 to form a sleeve portion 87 having, in order from the bottom of the bore 86, a bleed orifice 88 and two belts of circumferentially spaced radial ports 89 and 90 spaced longitudinally thereof. The outer end of the bore 86 is closed by a plug 91 to form an expansible chamber 92 intermediate the end of the valve member 83 and the fitting 77.

The chamber 92 is connected through the fitting 77 and piping 93 to an outlet fitting 94 of a remote control actuat ing device 95. The actuating device 95 comprises a cylinder body 96 having a bore 97 therein reciprocably mounting a plunger or piston 98 to form an expansible chamber 100 therebetween. A return spring 99 is compressibly interposed between the fitting 94 and the end of the plunger 98 and serves to maintain the plunger normally in the position shown in full lines in Figure 1. When the plunger is in this position, the chamber 100 is liquid-full being in communication through port 101 with a liquid reservoir 102 provided in the cylinder body 96.

Upon manual actuation of the plunger 98 to the right to its position shown by broken lines 98', the liquid entrapped in the chamber 100 as the plunger closes the port 101 is forced through the piping 93 into the actuating expansible chamber 92 of the control valve mechanism 32 thereby causing the valve member 83 to be actuated to the left. This movement of the valve member 83 in turn acts through the lever assembly 31 to shift the pinion gear 30 towards the engagement with the engine ring gear. The bleed orifice 88 and the ports 89 and 98 of the valve member 83 are spaced relative to the actuating geometry of the linkage or lever assembly 31 so that as the pinion gear engages the engine ring gear, the valve member 83 interconnects the valve inlet chamber with the intermediate chamber 80, thereby permitting flow of the pressurized fluid into the intermediate valve chamber first through the bleed orifice 88, the bore 86, and the ports and then through ports 89 and 9t} and the bore 86. As the pressure thus applied to the intermediate chamber 80, and hence to the chamber 70, equalizes the pressure acting on the opposite end of the valve member 62, the spring 66 shifts the valve member 62 into abutment with the stop ring 60. In this position the reduced diameter land 63 interconnects the ports 72 and 74 thereby supplying suflicient actuating fluid to the starter motor to permit rotation of the engine at a starting speed.

However, when tooth abutment occurs between the pinion 30 and the engine ring gear, the actuating fluid applied to the chamber 92 by the remote control actuating device is ineffective to shift the valve member 83 beyond its intermediate bleed position until after proper tooth engagement has been initiated. Full accumulator pressure is applied to the intermediate valve chamber 80 and the chamber 70 when the valve member 83 is in this intermediate bleed position. Consequently, the valve member 62 is shifted by the spring 66 to its opened position. However, since the bleed orifice 88 permits only a limited flow of pressurized fluid to the starter motor, the motor is rotated very slowly until the starter pinion has been brought into meshing alignment with the engine ring gear. When such alignment has been effected, actuating pressure applied to the control valve member 83 simultaneously shifts the control valve member to its full-opened position and shifts the pinion into engagement with the engine ring gear whereupon the starter motor drives the engine at a starting speed.

Upon engine starting, the engine tends to drive the starter device 21 through the pinion gear. However, the drag of the motor 21 causes the starter drive clutch mechanism 29 to overrun thus unloading and substantially reducing the pressure demand of the starter motor 21. The consequential pressure drop occurring between the inlet valve chamber 78 and the outlet 27 of the motor results in a pressure unbalance whereby the pressure applied to the chamber 68 is eflective to shift the valve member 62 to an intermediate position, wherein the reduced fluid pressure within the chamber 70 and biasing action of the spring 66 balance the pressure applied to the chamber 68, either closing the valve ports 72 and 74 or providing only a limited pressure throttling bleed connection therebetween. Should the engine stop after its initial start, the pressure load demand on the starter motor 21 will again increase, and as the pressure again builds up in the intermediate chamber 80, the valve member 62 will again be shifted to its full-opened position thus causing the starter device 20 to again rotate the engine at a starting speed.

After the engine starts and the operator releases the actuating plunger 98, the plunger 98 is returned to its initial position by the return spring 99, a port 103 in the cylinder body bleeding fluid pressure from behind the plunger back into the reservoir. This return of the plunger 98 to its initial position tends to withdraw the actuating liquid column from the expansible chamber 92 thus. returning the valve member 83 to its initial position. However, to insure return of thepinion and starter drive mechanism and of the valve member 83 to their initial positions, the lever assembly 31 is biased to its initial position by a suitable by a suitable spring means such as by a torsion spring shown at 31'.

The form of the invention shown in Figure 2 is identical with the form shown in Figure 1 except for the remote control valve actuating mechanism; the accumulator pressure being utilized to actuate the valve member 83 to its valve-opened position through the operation of a remote control valve 110 and a valve actuating servo device 130 which replace the remote control device 95 and the pressure fitting 77, respectively, of the embodiment of Figure 1. Consequently, corresponding elements in Figure 2 have been designated by the same reference numerals and the following description of this embodiment is restricted to these diflerences.

The remote control valve 110 comprises a valve body 111 having a bore 112 extending therethrough. The bore 112 is closed at one end by a pressure fitting 113 which serves as a pressure relief port and is connected to the inlet 49 of the reservoir 35 by piping 114. The bore 112 is undercut intermediate its ends to provide a pressure inlet port or chamber 115 which is connected to the accumulator through piping 116, 46 and 43 and the manual valve 44. A second undercutting of the bore 112 provides an outlet port or chamber 117 which is spaced longitudinally of the inlet port and is connected through piping 118 to the valve actuating. servo device 130. A plunger type valve member 119 is reciprocably mounted in the bore 112 and is normally biased to an off position, corresponding to the position shown in full lines in Figure 2, by a spring 120 compressibly interposed between the fitting 113 and the adjacent end of the valve member 119. In its ofi position, annular boss 121 formed on the end of the valve member abuts an annular shoulder formed by counterboring. the valve body adjacent its closed end. The valve member is provided with bores 124 and 126 extending axially thereof from its opposite ends. The outer end of the bore 126 is sealed by a plug 126. When the valve member 119 is in its ofi position, as shown, a small orifice or port 125 interconnecting the outer surface of the valve member with the bore 124 mates with the port 117 and bleeds hydraulic fluid from the valve actuating servo device to the reservoir through the piping 114. When the valve member 119 is manually shifted to its position 119' indicated in broken lines through suitable actuating mechanism such as a foot pedal 129, as shown, two radial orifices or ports 127 and 128 spaced longitudinally of the valve member and interconnecting the outer surface thereof with the bore 126 serve to interconnect the valve inlet port 115 with the outlet port 117 thereby metering pressurized fluid to the valve actuating device 130 through the piping 118.

The valve actuating device 130 comprises a cylinder 'body 131 adapted to replace the pipev fitting 77 mounted in the end of the bore 54 in the embodiment of Figure 1. The cylinder body 131 has a bore therein 132 which reciprocably mounts a plunger or piston 133. It will be noted that the piston 133 is of substantially smaller diameter than the end of the valve member 83 and conprinciples of the invention and the best known meansof putting the invention into practice. However, it is to be understood that many modifications of structure may be made Within the scope and principles of the invention by the exercise of skill in the art, and the invention is not considered as limited by the foregoing description, the spirit and scope of the invention being defined in the following claims.

I claim:

1. In a fluid pressure system including a source of pressurized fluid, a pressure-operated actuator device, drive means for selectively and drivingly connecting said actuator device to a load mechanism, a valve mechanism operable to control the flow of pressurized actuating fluid from said source to said actuator device, said valve mechanism including a valve casing having a first and second valve chamber therein, each of said chambers having an inlet port and an outlet port opening thereon, a first passage means connecting the inlet port of said first chamber to said source, a second passage means connecting the outlet port of said first chamber to the inlet port of said second chamber, and a third passage means connecting the outlet port of said second chamber to said actuator device, a valve member mounted in each of said chambers and independently movable between a closed no-fiow position and an open full-flow position, means for selectively actuating said first chamber valve member between its closed and opened positions, a resilient means biasing said second chamber valve member towards its open position, a first pressure means responsive to the fluid pressure of said source and operably associated with said second chamber valve member to bias it to its closed position in opposition to said resilient means whenever said first chamber valve member is in its closed position, and a second pressure means responsive to the fluid pressure intermediate said chambers in said second passage and o-perably associated with the second chamber valve member to counterbalance the closing biasing action of said first pressure means thereby permitting said resilient means to shift said second chamber valve member to its opened position whenever said first chamber valve member is in its opened position and said actuator device is drivingly coupled to said load mechanism by said drive means, and said first and second pressure means and said resilient means coacting on said second chamber valve member to maintain it in an intermediate limited flow opened position whenever said first chamber valve is in its opened position and said actuator device is disconnected from said load mechanism by said drive means.

2. In a fluid pressure system including a source of pressurized fluid, a pressure-operated actuator device and means for drivingly connecting said actuator device to a load mechanism operable under variable load conditions, a valve mechanism operable to control the flow of pressurized hydraulic fluid from said source to said actuator device, said valve mechanism including a valve casing having a first and second valve chamber therein, each of said chambers having an inlet port and an outlet port opening thereon, a first passage means connecting the inlet port of said first chamber to said source, a second passage means connecting the outlet port of said first chamber to the inlet port of said second chamber, and a third passage means connecting the outlet port of said second chamber to said actuator device, a valve member mounted in each of said chambers and independently movable between a closed no-flow position and an open full-flow position, means for selectively actuating said first chamber valve member between its closed and'opened positions, a first pressure means associated with said second chamber valve member and continuously operable thereon to bias it towards its closed position in accordance with the fluid pressure of said source, and a second pressure means associated with the second chamber valve member and operable thereon in accordance with the fluid pressure in said second passage to oppose the-closing '7 biasing action of said first pressure means,'said second pressure means being effective when the fluid pressure in said second passage is above a predetermined pressure to shift said second chamber valve member to its opened position.

3. The combination as set forth in claim 2 in which said first and second pressure means are arranged to coact on said second chamber valve member to maintain it in an intermediate limited flow position whenever said first chamber valve is in its opened positioned and the fluid pressure in said second passage is below said predetermined pressure.

4. In a fluid pressure system including a source of pressurized fluid, a pressure-operated actuator device and means for drivingly connecting said actuator device to a variable load mechanism, a valve mechanism operable to control the flow of pressurized hydraulic fluid from said source to said actuator device, said valve mechanism including a valve casing having a first and second chamber therein, each of said chambers having an inlet port and an outlet port opening thereon, a first passage means connecting the inlet port of said first chamber to said source, a second passage means connecting the outlet port of said first chamber to the inlet port of said second chamber, and a third passage means connecting the outlet port of said second chamber to said actuator device, flow restricting means associated with said first chamber and operable to restrict the flow between its inlet and outlet ports, a valve member mounted in said second chamber and movable between a closed noflow position and an open full-flow position, a first pressure means associated with said valve member and operable thereon to bias it towards its closed position in accordance with the fluid pressure of said source, a second pressure means associated with said valve member and operable thereon in accordance with the fluid pressure in said second passage to oppose the closing biasing action of said first pressure means, said second means being effective to shift said valve member to its opened position when the fluid pressure diflerential between said second passage and said source is in excess of a predetermined ratio.

5. In the combination set forth in claim 4, said first and second pressure means being adapted to coact on said valve member to maintain it in an intermediate fluid throttling position when the fluid pressure differential between said second passage and said source is below said predetermined ratio.

6. In a fluid pressure system including a source of pressurized fluid and a pressure-operated rotary motor adapted to drive a variable load mechanism, a valve mechanism operable to control the flow of pressurized hydraulic fluid from said source to said motor, said valve mechanism including a valve casing having a valve chamber therein, said chamber having an inlet port and an outelt port opening thereon, a first passage means connecting said inlet port to said source and including a flow restricting means intermediate said inlet port and said source, and a second passage means connecting the outlet port of said chamber to the inlet of said motor, a valve member mounted in said chamber and movable between a closed no-flow and an open full-flow position, a first pressure means associated with said valve member and operable thereon to bias it towards its closed position in accordance with the fluid pressure intermediate said flow restricting means and said source, a second pressure means associated with said valve member and operable thereon to oppose the closing biasing action of said first pressure means in accordance with the fluid pressure intermediate said flow restricting means and said inlet port, said second means being effective to shift said valve member to its opened full-flow position when the differential ratio between the fluid pressure on the inlet port side of said flow restricting means and the fluid pressure on the fluid source side of said flow restricting means is above a predetermined value, and said first and second pressure means coacting on said valve member to maintain it in an intermediate fluid throttling position when said pressure diflerential is below said predetermined ratio thereby limiting the rotational speed of said rotary motor under reduced load operating conditions.

7. A valve mechanism operable to selectively control the flow of pressurized fluid from a source thereof to a pressure-operated device adapted to drive a load device, said valve mechanism comprising, in combination, a valve casing having two parallel bores, an inlet chamber and an intermediate chamber opening on one of said bores and spaced longitudinally thereof, an outlet chamber opening on the other of said bores intermediate its ends, a first passage connecting said inlet chamber to the adjacent end of said second bore, a second passage interconnecting said outlet chamber to said second bore opposite said outlet chamber, and a third passage of restricted size interconnecting said intermediate chamber with the end of said second bore opposite said first passage, said inlet chamber being connected to said fluid pressure source and said outlet chamber being connected to said pressure operated device, a first valve member reciprocably mounted in said first bore between a closed and an opened position and operable to control the flow of pressurized fluid from said inlet chamber to said intermediate chamber, a second valve member reciprocably mounted in said second bore and operable to control the flow of pressurized fluid from said intermediate chamber to said outlet chamber, said second bore being closed at both ends to define two opposed expansible pressure chambers with said second valve member, a spring biasing said second valve member in opposition to the inlet fluid pressure normally supplied to the expansible chamber in said adjacent end of said second bore, the inlet pressure applied to said adjacent expansible chamber being normally operable to maintain said second valve member in its closed position when said first valve member is in its closed position, and the fluid pressure applied to the eXpansible chamber in the opposite end of said second bore when said first valve member is in its open position balancing the fluid pressures acting on said valve member thereby permitting said spring to bias said second valve member to its open position.

8. In a fluid pressure starting system for an engine including a source of pressurized fluid, a pressure-operated motor device, drive establishing means operable to drivingly connect and disconnect said motor device and said engine, a valve mechanism operable to selectively control the flow of pressurized fluid from said source to said motor device, said valve mechanism comprising, in combination, a valve casing having two parallel bores, an inlet chamber and an intermediate chamber opening on one of said bores and spaced longitudinally thereof, an outlet chamber opening on the other of said bores intermediate its ends, a first passage connecting said inlet chamber to the adjacent end of said second bore, a second passage interconnecting said intermediate chamber to said second bore opposite said outlet chamber, and a third passage of restricted size interconnecting said intermediate chamber with the end of said second bore opposite said first passage, said inlet chamber being connected to said fluid pressure source and said outlet chamber being connected to said pressure operated motor device, a first valve member reciprocably mounted in said first bore between a closed and an opened position and operable to control the flow of pressurized fluid from said inlet chamber to said intermediate chamber, linkage means operably interconnecting said first valve mem ber and said drive establishing means, remote control means operable to shift said first valve member from its closed to its opened position thereby operating said drive establishing means to drivingly couple said motor device to said engine, a second valve member recip- 9 rocably mounted in said second bore and operable to control the flow of pressurized fluid from said intermediate chamber to said outlet chamber, said second bore being closed at both ends to define two opposed expansible pressure chambers with said second valve member, a spring biasing said second valve member in opposition-to the inlet fluid pressure normally supplied to the expansible chamber in said adjacentend of said second bore, the inlet pressure applied to said adjacent expansible chamber being normally operable to maintain said second valve member in its closed position when said first valve member is in its closed position, and the fluid pressure applied to the expansible chamber in the opposite end of said second bore when said first valve member is in its open position being operable to balance the fluid pressures acting on said second valve member thereby permitting said spring to bias said second valve member to its open position.

9. A hydraulic starting system for an engine including a source of pressurized hydraulic fluid, a pressure-operated motor device of a rotary type, means for drivingly connecting and disconnecting said motor and said engine including an overrunning clutch mechanism and a pinion gear shiftable to drivingly engage an engine drive gear, a valve mechanism operable to selectively control the flow of pressurized fluid from said source to said motor device and including a valve casing having two valve bores therein, an inlet port and an intermediate port opening on one of said bores and spaced longitudinally thereof, an outlet port opening on the other of said bores intermediate its ends, a first passage connecting said inlet port to the adjacent end of said second bore, a second passage interconnecting said intermediate port to said second bore opposite said outlet port, and a third passage of restricted size interconnecting said intermediate port with the end of said second bore opposite said first passage, said inlet port being connected to said fluid pressure source and said outlet port being connected to said pressure operated motor device, a first valve member reciprocably mounted in said first bore between a closed and an opened position and operable to control the flow of pressurized fluid from said inlet port to said intermediate port, a second valve member reciprocably mounted in said second bore and operable to control the flow of pressurized fluid from said intermediate port to said outlet port, said second bore being closed at both endsto define two opposed expansible pressure chambers with said second valve member, a spring biasing said second valve member in opposition to the inlet fluid pressure normally supplied to the expansible chamber in said adjacent end of said second bore, said inlet pressure being normally operable to maintain said second valve member in its closed position when said first valve member is in its closed position, and the fluid pressure applied to the expansible chamber in the opposite end of said second bore through said third passage when said first valve member is in its open position being operable to balance the fluid pressures acting on said second valve member thereby permitting said spring to bias said valve member to its open position, and means for shifting said pinion gear into engagement with said engine driven gear and for simultaneously shifting said first valve member between its closed and opened positions to permit the flow of pressurized fluid from said inlet port to said outlet port after said pinion gear initially engages said engine driven gear.

10. The combination as set forth in claim 9 in which said last-mentioned means includes linkage means operably interconnecting said first valve member and said pinion gear, an expansible chamber actuating mechanism operable to shift said first valve member from its closed position to its opened position thereby shifting said pinion gear into engagement with said engine driven gear and a remote control pressure supply means operable to supply actuating fluid to said actuating mechanism.

7 11. The combination as set forth in claim 9 in which said last-mentioned means includes linkage means operably interconnecting said first valve member and said pinion gear, a passage means interconnecting said adjacent end of said first bore and a cylinder, said cylinder having a plunger reciprocably mounted therein and adapted to force a column of hydraulic fluid through said passage to force said first valve member from its closed to open positions thereby shifting said pinion gear into engagement with said engine-driven gear.

12. The combination as set forth in claim 9 in which said last-mentioned means includes linkage means operably interconnecting said first valve member and said pinion gear, a pressure-operated actuating mechanism associated with and operable to shift said first valve member, said linkage means, and said pinion gear to initiate their engine starting operations, and a remote control valve means operable to supply actuating fluid pressure from said source to said actuating mechanism.

13. A hydraulic engine starting system for an engine including a source of pressurized hydraulic fluid, a pressure-operated rotary motor, a starter drive mechanism adapted to dri-vingly connect said motor to said engine and including an overrunning clutch and a pinion gear shiftable to drivingly engage an engine-driven gear, a valve mechanism operable to selectively control the flow of pressurized fluid from said source to said motor, said valve mechanism including a valve casing having an inlet port connected to said fluid pressure source and an outlet port connected to said pressure-operated motor and a valve member movable between a closed and an opened position and operable to control the flow of pressurized fluid between said inlet and outlet ports, linkage means operably interconnecting said valve member and said pinion gear so as to permit the flow of pressurized fluid from said inlet port to said outlet port after said pinion gear initially engages said engine-driven gear, a pressureoperated means associated with and operable through said linkage means to shift said pinion gear toward engagement with said engine-driven gear and to simultaneously shift said valve member from its closed position toward its opened position, and a remote control pressure supply means operable to supply pressurized actuating fluid to said actuating mechanism.

14. In the combination set forth in claim 13, said pressure-operated means including an expansible chamber actuating device and said remote control pressure supply means including a cylinder reciprocably mounting a piston to define a second expansible chamber, means for selectively reciprocating said piston between two extreme positions, passage means connecting the expansion chamber of said pressure-operated actuating device to the expansion chamber of said remote control pressure supply means, said expansible chambers and said passage means being liquid full whereby selective reciprocation of said remote control piston in one direction forces hydraulic fluid through said passage means into the expansible chamber of said pressure-operated actuating device thereby causing said actuating device to shift said valve member towards its open position and simultaneously shifting said pinion gear towards gear engagement.

15. In the combination set forth in claim 13, said pressure-operated means including an actuating cylinder having a piston reciprocably mounted therein to define an expansible chamber therebetween, said piston being operably connected to said valve member, and said pressure supply means comprising a passage means connecting said expansible chamber to said source of pressurized hydraulic fluid and including a second valve mechanism selectively operable to control the flow of actuating fluid from said source to said actuating expansible chamber.

16. An engine starting system for an engine including a source of pressurized fluid, a pressure-operated motor,

a starter drive mechanism adapted to drivingly connect said motor to said engine and including an overrunning clutch and a pinion gear shiftable to drivingly engage an engine-driven gear, said overrunning clutch being operable to disconnect said pinion gear from said motor upon starting of said engine, a first valve means including a first valve member selectively movable between a closed and a full opened position and operable to control the flow of pressurized fluid from said source to said motor, a second valve means including a second valve member automatically operable between a closed and an opened position to control the flow of pressurized fluid from said source to said motor in accordance with the driving connection established between said motor and said engine, linkage means operably interconnecting said first valve member and said pinion gear so as to permit the flow of pressurized fluid from said source to said motor after said pinion gear initially engages said engine-driven gear, a first pressure-operated means associated with and operable to shift said pinion gear toward engagement with said engine-driven gear and to simultaneously shift said first valve member from its closed position toward an opened position, said movement of said first valve member to an opened position occurring after initial gear engagement, a remote control pressure supply means selectively operable to supply pressurized actuating fluid to said first pressure operated means, and a second pressure-operated means automatically operable to shift said second valve member from its closed to its opened position whenever said first valve member is in an opened position and said motor is drivingly connected to said engine.

17. An engine starting system for an engine including a source of pressurized fluid, a pressure-operated motor, a starter drive mechanism adapted to drivingly connect and disconnect said motor to said engine, a first valve means including a first valve member selectively operable between a closed and a full opened position to control the flow of pressurized fluid from said source to said motor, a second valve means including a second valve member automatically operable between a closed and an opened position to control the flow of pressurized fluid from said source to said motor in accordance with the driving connection established between said motor and said engine, means operably interconnecting said first valve member and said starter drive mechanism so as to permit the flow of pressurized fluid from said source to said motor only after a driving connection has been established between said motor and said engine, a first pressure-operated means associated with and operable to shift said first valvememberirom its closed position toward an opened position, a remote control pressure supply means selectively operable to supply pressurized actuating fluid to said first pressure-operated means, and a second pressure-operated means automatically operable to shift said second valve member from its closed to its opened position whenever said first valve member is in an opened position and said motor is drivingly connected to said engine.

v18. In the combination set forth in claim 17, said first pressure-operated means including an expansible chamber actuating device and said remote control pressure supply means including a cylinder reciprocably mounting a piston to define a second expansible chamber, means for selectively reciprocating said piston between two extreme positions, passage means connecting the expansion chamber of said pressure-operated actuating device to the expansion chamber of said remote control pressure supply means, said expansible chambers and said passage means being liquid full whereby selective reciprocation of said remote control piston in one direction forces hydraulic fluid through said passage means into the expansible chamber of said pressure-operated actuating device thereby causing said actuating device to shift said first valve member towards its open position.

19. In the combination set forth in claim 17, said first pressure-operated means including an actuating cylinder having a piston reciprocably mounted therein to define an expansible chamber therebetween, said piston being operably connected to said first valve member, and said pressure supply means comprising a passage means connecting said expansible chamber to said source of pressurized hydraulic fluid and including a third valve means including a third valve member selectively operable between a first position and a second position, said third valve member being adapted when in said first position to establish flow of actuating fluid from said source of said actuating expansible chamber thereby causing said actuating cylinder to shift said valve member toward its opened position and when in said second position to vent said actuating expansible chamber thereby permitting return of said first valve member to its closed position.

References Cited in the file of this patent UNITED STATES PATENTS 1,823,426 Ferris Sept. 15, 1931 FOREIGN PATENTS 942,178 Germany Apr. 26, 1956 

